Improvement in rotary valves for steam-engines



G. WESTINGHUUSE, Jr.

Rotary-Valves for Steam-Engines.

NO. 138,828. i Patented Mayl3,l873.

UNITED STATES PATENT EEICE.

GEORGE WESTINGHOUSE, JR., OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT INROTARV VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. l 38,828, dated May 13,1873; application filedv February 15, 1873.

To all whom it may concern:

Beit known that I, GEORGE WEsTINeHoUsE, Jr., of Pittsburg, in the countyof Allegheny and State of Pennsylvania, have invented ay new and usefulImprovement in Rotary Valves for Steam-Engines; and I do hereby declarethe following to be a full, clear, and exact description thereof.

My present invention relates to improvements in the class ofsteam-engines described in patents' granted to me August 30, 1870, No.106,899; June 6, 1871, No. 115,668; and October 8, 187 2, No. 131,985and more particularly to the devices by means of which the auxiliary orreversing engine therein shown is operated.

To enable others skilled in the art to make and use my invention, I willproceed to describe its construction and mode of operation, referringfor that purpose to the accompanydrawing making a part of thisspecification, in which- Figure 1 is a vertical sectional view throughthe axial line of the reversing-cylinder, through the valve-chamber atright angles to the axial line of the valve, and down through the baseblock, which rests on or constitutes the upper v head of the maincylinder. Fig. 2 is a sectional view through w :v of Fig. 1. Fig. 3 is adetached view of the valve devices of Figs. 1 and 2, but drawn out onthe valve-stem so as to give a separate view-of each; `and Figs. 4 and 5are detached views of parts, hereinafter described.

Like letters of reference indicate like partsk in each.

r[he auxiliary or reversing cylinder B, the valve-box B1, and base blockB2 are substantially of the. same construction, relative arrangement,and operation as in the patents above named, as also are the piston l)with its stem and eye D', and the valve-stem f, knob j 2, and shoulderf1. The valve u is also made as in patent No. 131,985, except that thesteamport s is made in its periphery, two exhaustrecesses, u c, onopposite sides, with suitable exhaust-ports, take the place of theexhaust` groove there shown, and an oil-groove, s', is made alonglengthwise of the lower periphery for convenience in keeping the valvewell oiled. rlhe valve-seat m is of the same construction and operationas in the patent last named.

The other steam-ports are also the same, ex-

cept that an exhaust-port, c', leads from one recess t to the oppositeexhaust -port w, for reasons which are apparent on examination of thedrawing.

In` the present improvement the valve-stem g, on which is arranged thevalve u and the rocking block g', has a collar, e, near one end, in suchposition that the end of the valve a will bear against it; then thesteam that leaks past the valve and that end of the stem will so farcounterbalance the steam pressure on the other end ofthe valve n thatthe latter while workin g closely on its seat will not wedge in sotightly as to occasion serious loss by excessive friction. The oppositeend of the stem g passes through a stuffing-nut in the valvebox Bl so asto be capable of a free end play, so far as may be necessary to relievethe valve of excessive friction. The rocking block g has a sleeve, t',which passes through the valve u, and dowel-pins t1 t2, by which it isconnected with the valve. On one of these pins, il, I slip the slottedeye h, which is made in the upper end of the stem f. This eye .is longenough to allow the pin il to play back and forth so far as may benecessary in. its rotary motion. By means of this stem and crank motionthe valve is rotated back and forth so as to bring the steam-port salternately to the ports c c', which ports communicate by the ports o owith the opposite ends of the cylinder B; also, by the same motion therecesses@ o are alternately brought into communication with theexhaustports u u', and z z', and o t' so as to carry off the exhauststeam to a common exhaust-port, w. Steam is admited into the chamber bby any suitable port, a.

Ihave found in practice that where the steam is allowed to press on theupper end of the enlarged part f1 of the stem f such pressure wassometimes suicient to force the stem down before the main piston in itsdownward stroke strikes the knob f2. To remedy this defect I make thestem f above the shoulder f1, as at r1, of less size-say, about the sizerequired in the main part f 1 of the stem-and surround this reduced partr1 with a bush, r, which may conveniently be made in two partsand whichis supported against the downwardy pressure of the stem by resting on ashoulder, r2, of the base B2. In this way I reduce the area of stemsubject to effective downward pressure to suoh extent that the valve ais not liable to be reversed thereby.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The eonieal valve n subject to steam pressure at its larger end, incombination with the stem g, on which it rotates, and the collar e onsaid stein with a bea-ring against the smaller end of the valve, theopposite end of the stem g passing through a stuffing-nut so as to havea free end play, substantially as set forth.

2. The stein f having,` a shoulder, f1, and a reduced part, r1, above,in combination with a hand.

GEORGE WESTINGHOUSE, JR.

Witnesses:

A. S. NrouoLsoN, G. H. CHRISTY.

